Pretty sure one of the major plot points set up since the opening scenes of the expansion was that Rastakhan had become an overconfident, overproud, lame duck of a king, and Talanji was the actual hope of the Zandalari. Rastakhan being lax with the defenses because "our fool enemies will kill themselves trying to defy us", seems pretty par for the course for him.

My first month in BFA alliance raided Dazar'alor at 2am and slaughtered us all. I was backing up to the market area with that huge pterodactyl in top with the npc riding it thinking "oh man they are going to get it now" and they destroyed it in two seconds. There was absolutely nothing in the city the gave them a challenge. That has been in the back of my head the whole time this raid has been approaching. In open world they can roll the whole city but in a raid it becomes super difficult?

The reason the warfront troops don't attack is because they don't exist on the screen if you aren't 120. So a level 118 troll would see the Alliance player being damaged by nothing. It's not a good reason, but it's the reason.